1. Field of the Invention
The present invention relates to apparatus and method for recirculating electrolyte of a electric storage battery. More particularly, the present invention provides apparatus and method for removing, treating, and replacing electrolyte of a multiple cell industrial-type battery.
2. Description of the Prior Art
Large industrial batteries are widely employed today in many industries. These batteries are commonly used to power various stationary systems, such as telephone exchanges, as well as many forms of mobile equipment, such as fork lift trucks. Despite wide spread use of such batteries and the many commercial and environmental advantages they provide, the problems inherent with the operation of industrial batteries prevent them from being even more widely utilized.
Most of the problems associated with industrial batteries is that they require constant service during their normal operation of repeated discharging and recharging.
The first problem with these batteries is that they require constant addition of water to compensate for losses due to evaporation and electrolysis during charging. Manual watering of battery cells is generally time consuming and expensive. It is also an unpleasant task so watering is often ignored to the detriment of the battery's performance and longevity.
A second problem is that batteries get hot, particularly those in severe, deep-cycle service. High battery temperatures have a very damaging effect on a battery's durability. In general, battery cooling systems have been complex and expensive. They are used in submarine and other exotic applications, but seldom in commercial battery designs. A third and related problem is that rapid re-charging causes heat buildup in a battery. Therefore, the rate at which a battery can be charged is limited by the lack of a cooling system. Since fast charging has a great appeal to some battery users, this limitation has far-reaching commercial repercussions.
A fourth problem is that batteries produce hydrogen and oxygen gasses during charging which can cause explosions if the gasses are not properly vented. This forces a user to ventilate the battery charging room which adds to heating and cooling costs of the space. A fifth and related problem is that some lead-acid batteries are made with special alloys suitable for deep cycle service on fork lift trucks and similar equipment. These batteries can produce poisonous gasses containing stibene (antimony) and arsine (arsenic). Again, forced ventilation is required.
A sixth problem is that batteries are often watered incorrectly, causing flooding of battery electrolyte from the cells causing corrosion and damage to vehicles and property. A seventh and related problem is that when electrolyte is lost from the battery cells, it must be replaced. This is a difficult procedure, not without danger, and one often ignored to the detriment of battery performance.
An eighth problem is that, during cycling, battery plates tend to shed active material and cause short circuits in the cells. Various separators and protective devices are used to counter this action, but ultimately many batteries fail due to these short circuits even though they may otherwise be in good condition. Existing battery designs do not allow for the replacing or filtering of electrolyte.
Additionally, in order to maximize the life of the battery and to assure full performance, it is known that adequate rest period and cooling of the battery is important prior to reinstallation. This rest period, which generally requires up to eight (8) hours unassisted, is necessary to dissipate heat generated due to build up of ohmic resistances during discharge and the chemical reconversion of active materials in the charge regime.
Due to time constraints, many users ignore the battery manufacture's instructions concerning adequate time for cool down. This results in seriously shortened battery life. The heat problem in batteries is complicated by the fact that battery cells located in the interior of a multiple cell battery have significantly less exposed surface area to permit cooling and are therefore prone to premature aging relative to the rest of the battery.
In an attempt to solve some of these problems, a number of partial solutions have been suggested. In U.S. Pat. No. 1,837,242 issued Dec. 22, 1931, to Meyer, an apparatus is disclosed for filling multiple battery cells simultaneously. Although this system may solve the limited watering problem, it does not solve heat build-up problems or permit removal and treatment of electrolyte. Such devices have the additional problem of water line freeze-up at low temperatures which can limit their use. Another partial solution may be found in U.S. Pat. No. 4,415,847 issued Nov. 15, 1983, to Galloway. In that patent a method and apparatus is proposed for providing a cooling liquid, such as anti-freeze, to the battery to help to reduce heat build-up. Unfortunately, this system appears far too complex for practical implementation, and it does not address any of the other maintenance problems discussed above.
Applicant is aware of at least one previous proposal for the removal and cooling of electrolyte on an experimental basis. This method called for the electrolyte to be piped out the battery cells under pressure via one output manifold; the electrolyte was then pumped into an external tank of cool electrolyte and then piped back again through a separate second input manifold. Although this system met with some limited experimental success, it is believed that it has not been implemented beyond experimental applications due to a number of practical problems.
The experimental electrolyte recirculation system created a number of new problems which have seriously limited its acceptance. One major problem with this system was that the multiple manifolds were too cumbersome and complex for use with production batteries. As such, the system required substantial modification of commercial battery design, as well as installation, surveillance and maintenance of numerous hoses and connections. Moreover, the positive pressure driving the system actually multiplied maintenance problems--such as causing leaks, hose connection blow off, and increased gas pressure hazards.
Accordingly, it is a primary object of the present invention to provide an method and apparatus for battery maintenance which cools electrolyte, decreasing charging time and improving battery life, while also automatically watering the batteries and equalizing electrolyte concentration between battery cells.
It is a further object of the present invention to provide such a method and apparatus which readily permits the removal of electrolyte from the battery for temperature adjustment or other treatment and its automatic return to the battery.
It is an additional object of the present invention to provide such a method and apparatus which is easily implemented with existing battery designs, and which may be practically employed on commercial vehicles and in other applications with minimal installation time and on-going supervision.
It is another object of the present invention to provide such a method and apparatus which is of limited size and complexity so that it may be employed on commercial vehicles to allow the treatment of electrolyte while the battery is in use.
It is yet another object of the present invention to provide a method and apparatus that will allow more efficient, convenient, economical and safe charging of batteries during the manufacture of the batteries themselves.
Other objects of the present invention should become evident from review of the following specification.